New Virtual Institute for Plasma Acceleration

The Helmholtz Association will fund a new Virtual Institute at DESY which will advance a novel accelerator technology. Plasma wakefields have the potential toaccelerate particles over very short distances, thus offering a promising technology for future accelerator applications. The newly established Virtual Institute “Plasma wakefield acceleration of highly relativistic electrons with FLASH” will do basic research to explore the possibilities of using the extremely high electric fields created in a plasma to reliably accelerate high-energy electrons. The Helmholtz Association will fund the institute for a period of five years.

Simulation of an electron bunch in a laser driven plasmawave.

A plasma is a highly excited state of ionized matter, with electrons moving freely between the atomic nuclei. It is, for example, generated by an intense laser beam or by a particle beam in a gas. Initial experiments at other institutes to use these fields for particle acceleration have had very promising results. One of the major challenges is to shoot a particle bunch into the plasma at exactly the right time when it is accelerated; an experiment which has not been carried out so far. This is one of the topics of the new virtual institute which involves the University of Hamburg, Max Planck Institute in Munich, John Adams Institute (Great Britain), as well as the accelerator centres SLAC, LBNL (both USA) and CERN. The scientists will inject the electron beam of the FLASH II accelerator into a plasma cell, thereby accelerating it with the plasma. At one of the planned experimental setups, the plasma will be created by the particle bunch itself; in another approach, the plasma will be produced by an extremely intense laser.

“With FLASH, we have the ideal facility to make a big step forward with this kind of research” says Prof. Brian Foster, Alexander von Humboldt Professor at the University of Hamburg and DESY, spokesman of the virtual institute. “The high-energy electrons from FLASH II have a very precise spatial and temporal structure and are perfectly suited to characterise the plasma. Eventually, we want to accelerate reliably not only single electrons but the whole bunch. To achieve this, we still have to put a lot of effort into our beam diagnostics – to synchronise the plasma and electron beam, femtoseconds make the difference.”

The expertise for these experiments which has already been developed in the Helmholtz Alliance “Physics at the Terascale” and the portfolio theme “Accelerator Research and Development” (ARD) will now be applied in the framework of the new Virtual Institute. Measurements will take place parasitically to normal FLASH user runs; the plasma accelerator scientists in the VI also plan experiments at REGAE (Relativistic Electron Gun for Atomic Exploration) in Hamburg and at PITZ (Photo Injector Test Facility in Zeuthen).